Polymerase chain reaction to search for Herpes viruses in uveitic and healthy eyes: a South African perspective

Abstract

Abstract:Objective: To analyse aqueous polymerase chain reaction (PCR) results in patients diagnosed with undifferentiated uveitis and determine prevalence of herpesviridae in non-uveitic patients undergoing routine cataract extraction. Design: Retrospective comparative case series and prospective cross-sectional study. Subjects: 72 patients with idiopathic uveitis and 57 surgical patients. Methods: Diagnostic aqueous paracentesis with PCR testing for 6 herpes viridae in uveitic patients. Anterior chamber paracentesis immediately pre-operative in the prospective arm, with PCR testing. Results: In the retrospective review we had a 47.2% positive PCR yield. Data analysis revealed a statistically significant correlation between a positive yield and being HIV+ (p=0.018); between an EBV+ yield and being HIV+ (p= 0.026) and a CMV+ result and being HIV+ (p=0.032). Posterior uveitis (p=0.014) and symptoms <30 days (p= 0.0014) had a statistically significant yield. In the prospective arm of the study: all 57 patients were HIV-and all aqueous samples were negative for the 6 herpesviridae. Conclusion: We recommend PCR testing for Herpesviridae as a safe second line test for patients with undifferentiated uveitis. We were unable to establish prevalence and suggest that the idea of a commensal herpes virus is unlikely if the blood-ocular barrier is intact.

The Usefulness of Aqueous Fluid Analysis for Epstein–Barr Virus in Patients with Uveitis

“…We noted a lower PCR yield for EBV (3/201; 1%) when compared to previous literature (up to 17%). 5,6,13,14 The prevalence of GWC was not systematically performed in the past except one study, which reports on 3/82; 4% prevalence of positive EBV GWC in uveitis patients (out of which 1 had a higher GWC for VZV), which is similar to 9% found in the present study. 5 It should be however noted that the GWC results in our study were typically low and/or combined with multiple positive GWCs.…”

“…This phenomenon is supported by previous studies, in which PCR was more often positive for EBV in HIV positive patients with large areas of retinitis compared to cataract controls. 5,6 The common prevalence of immunosuppression (by HIV or immunosuppressive medication) in patients with positive PCR for EBV in intraocular fluids was made earlier. 6,13,14 In our study, solely 3 patients were PCR positive out of whom one was immunosuppressed; this limited number precludes any meaningful comparisons.…”

“…1,3,4 Subsequently, more systematic reports emerged on this presumed association, reporting on polymerase chain reaction (PCR) positive for EBV in aqueous fluid of uveitis patients (up to 17%); however, these positive PCR results were also found in uveitis of other established causes and even in non-uveitis eyes (7%), especially in patients with severe ocular disorders and break down of blood-retina barrier. [4][5][6][7][8][9][10][11][12] In one study examining the viral loads of EBV PCR positive patients, intraocular viral loads were always lower when compared to blood levels, which does not support the presumptive replication of EBV within the eye. 13,14 Herein we report on a large series of uveitis patients who underwent diagnostic intraocular fluid assessment by both PCR and GWC for EBV in addition to Herpes Simplex Virus (HSV), Varicella Zoster Virus (VZV), Cytomegalovirus (CMV), Rubellavirus (RV) and report on the clinical characteristics of patients with laboratory findings indicative of intraocular EBV infection.…”

Herpesviridae prevalence in aqueous humor using PCR

“…These results are consistent with a related study in which no herpes viruses DNA was detected in aqueous humor from normal cataract patients 15 or HIV-negative patients. 16 We were unable to prove a significant correlation in detecting the Herpesviridae family between aqueous humor and serum. Therefore, the serology test proved unreliable in diagnosing viral uveitis because of the high number of false positives.…”

“…The formula used in this study to calculate the sample size for the prevalence rate 8 of 26.36% or 0.2636 at 95% confidence interval ( α =0.05) was N = z 2 × p × q / d 2 ( Z =1.96, P is the prevalence, Q =[1− P ], and d is the error margin [±10%]). The sample size needed for this study was at least 75 participants.…”